This invention relates to an anchor insert adapted to be embedded in a concrete slab for cooperation with a pick-up unit which includes a locking stem having a pair of lift shoulders extending from opposite sides of the stem.
An anchor insert as contemplated by the invention is constructed of a plurality of rod or heavy wire sections which become embedded in a concrete slab and serve as anchor members for lifting the slab. Portions of the anchor rod sections are shielded from the surrounding concrete, and a concrete-excluding hollow cage or can has been employed for this purpose in the insert, the cage being constructed of plastic, metal or other suitable material. A plurality of inserts may be embedded at different locations in the slab. A pick-up unit is provided for each insert, and the unit is designed for releasably interengaging the insert. Hoisting apparatus is connected to the pick-up units when engaged with the inserts. The slab may be raised from the horizontal position in which it is poured, to an upright position in which it may serve as a building wall, for example. The pick-up units are removed from their engagement with the inserts and may be used repeatedly with inserts in other slabs.
U.S. Pat. No. 3,431,012 discloses an anchor insert and a pick-up unit of the general type with which the present invention is concerned. U.S. Pat. application Ser. No. 435,700, filed Jan. 23, 1974 for Anchor Insert For Embedment In A Concrete Slab, now abandoned, and the continuation thereof, application Ser. No. 568,585, filed Apr. 16, 1975, disclose an anchor insert constituting an improvement on the structure of the patent. The anchor insert of the present invention is an improvement upon and provides advantages over the insert of the foregoing applications.
The anchor inserts are designed to be set upon the floor of a concrete slab form, and they are secured in place by wiring their parts to the reinforcing bars for the slab. However, the inserts frequently are subjected to forces tending to displace and/or damage them, such as the forces applied by striking the inserts with shovels and other equipment, and by workmen stepping on some part of the insert. The forces to which the inserts are subjected may move around or tilt the inserts, damage their cage members, which preferably are constructed of plastic, so as to permit leakage of mortar into the cage, and/or destroy the support for the cage members. It would be disadvantageous if the insert structure could be improved so as to minimize such problems, thereby insuring that the inserts are properly situated, and eliminating the time wasted in resetting or replacing inserts which have been moved out of place or damaged.